Improvements in methods of producing electrolytic anode assemblies

ABSTRACT

Methods are provided of producing electrolytic diaphragm cells are provided comprising a plurality of vertical substantially flat and hollow anodes formed, as regards at least one of their two substantially parallel faces, by a sheet of a film-forming metal, said anodes being secured to the base of the cell by means of extended portions which pass through the base, characterized in that the extended portions comprise a core made of a metal which is a good electrical conductor, which core is covered by a sheath made of a film-forming metal, a good electrical contact being ensured between the sheath and the core.

Umted States Patent 1 1111 3,928,167

Buoy et al. Dec. 23, 1975 IMPROVEMENTS IN METHODS OF [56] ReferencesCited PRODUCING ELECTROLYTIC ANODE UNITED STATES PATENTS ASSEMBLIES1,955,728 4/1934 Allen et al. 29/441 [75] Inventors: Pierre Buoy,Enghien-les-Bains; 2,092,353 9/ 1937 29/508 D i l Masure, La Madeleine;Paul 1;; 92/3/7404:

c a an E2322 rgggiz f igxg g 3,591,483 7/1971 Loftfield et al. 204/252 99 3 Levallois-Perret, all of France Primary Examiner R. L Andrews [73]Assignee: Rhone-Progil, Paris, France 22 Filed: May 15, 1974 [57]ABSTRACT Methods are provided of producing electrolytic dia [21] Appl470167' phragm cells are provided comprising a plurality of Related US.A li ati D t vertical substantially flat and hollow anodes formed, [62]Division of S No 316 515 D e c 19 1972 as regards at least one of theirtwo substantially parallel faces, by a sheet of a film-formin metal,said and b d h b f h g 1] b f 30 Forei A 5 ti D ta 0 es emg secure tot easeo t ece ymeanso 1 D 23 1 ca on lonty a 46296 extended portions whichpass through the base, charec. rance acterized in the extended portionscomprise a core made of a metal which is a good electrical con- 8204/286 ductor, which core is covered by a sheath made of a [58] Fie'ld290 R film-forming metal, a good electrical contact being en- 204/286sured between-the :sheath and the core.

2 Claims, 4 Drawing Figures IIII/IIIIIIIA US. Patent Dec. 23, 1975Sheet10f2 3,928,167

U.S. Patent Dec. 23, 1975 Sheet 2 of2 3,928,167

IMPROVEMENTS IN METHODS OF PRODUCING ELECTROLYTIC ANODE ASSEMBLIES Thisapplication is a division of our copending application, Ser. No.316,515, filed Dec. 19, 1972.

, BACKGROUND OF THE INVENTION .The present invention relates toelectrolytic diaphragm cells provided with flat and hollow-metal anodeswhich are formed, at least as regards one of their two parallel faces,by an apertured sheet or a lattice made of titanium or a metal or alloyhaving similar anodic properties. The anodes are also provided withextended portions for the inputof electric current and for fixing theanodes to the bases of the cells.

The advantages are known of using titanium or metals or alloys havingsimilar properties instead of graphite anodes in electrolytic cells,with such anodes being covered with a conducting metal which is notattacked by the electrolytic solutions. In particular, French Pat, No.1600249 describes constructions in which such metal anodes are extendedby metal portions for secur-. ing them to the base of the cells, and forthe input of the electrical current. 1

It is an object of the present invention to provid processes ofproducing electrolytic diaphragm cells having improved anodes.

It is also an object of the present invention to provide electrolyticdiaphragm cells having anodes which permit a more favorable distributionof electrical current.

These and other objects will be apparent to those skilledin the art fromthe present description, taken in conjunction with the. appendeddrawings, in which:

' FIG. 1 is an elevational view of an anode of the invention.

FIG. 2 is an elevational view of the lower part of the anode of FIG. 1having an extended portion fastened to the base of a cell.

FIG. 3 is aneelevational view of anotheranode extended portion fastenedto the base of a cell.

FIG. 4 is an elevational view of the lower part of an anode extendedportion fastened to the base of the cell,

with the electrical connection to the core portion.

GENERAL DESCRIPTION OF THE INVENTION The improved constructionsnowdescribed of the present inventionuse extended portions comprising acore made of a material which is a good electrical concluctor, thecorebeing covered with a sheath of titanium or other film-forming metal oralloy having similar anodic properties, so that a perfect electricalconnection is ensured between the'sheat'h and the core.

and can be welded to the faces of the anodes in such a way thatthe mostfavourable distributionof the electrical current is ensured at thatpoint. i

In practice, depending on the dimensions of the an odes and theirelectrical characteristics, one or more of such extended portions isused per anode, the use of a single extended portion enjoying 'theadvantage, however, that it is notsubjeeted to forces due to expansionof the elements of the anode. Extended portions of this nature arepreferably made'from jointly drawn members which are cylindrical inshape. It is easy to see that such a cylindrical shape permits variousmachining operations for ensuring a current feed to the extendedportions. V i

A first way in which electrical current can be supplied comprisesexposing the conducting core of the extended portion at its lower endwhich passes through the base of the cell. This permits securing to thecore in various known manners the current supply leads. It also providesfor a screw-thread on the sheath where it passes through the base, andsecuring thereto by weld ing above the screw-th'read'a washer of thesame or a similar metal, and thus to'tighten the extended portions tothe cell base. Also provided is sealing by means of a sealing gasket,which is preferably toric or toroidal, interposed between the washer andthe base. The current supplyleads can be securedto the base of the celland, if the base is metal, they can then act as a general current inputfor the anodes.

Another way in which the electrical current can be supplied to theextended portions of the anode in the case'where the base of the cell isof metal, comprises gripping the conducting core of theextended'portions of the anode, which is bared or exposed where itpasses through the'base of the cell, by the metal of which the baseitself is made. This gripping effect can be achieved by simply makingthe core have a force or frictional fit in the base. However, it ispreferably achieved by shrink-fitting, by establishing before assembly asufficient temperature difference between the base and the extendedportions of the anode, for example, by immersing the latter in liquidnitrogen before fitting. Upon expansion where returning to atmosphericor elevated temperature, alight fit is possible. Dismantling, ifrequired, can be effected by various means which can be used incombination, and which can include 1 screw extractors, (2) by providingthe various anchorages required, (3) conical machining of the core ofthe extended portions, (4) passages provided in the core so that acooling fluid can be circulated therein, and (5) means for heating'thebase. In this second way of feeding the electrode with current, it isobvious that sealing can be effected in a similar manner to thatdescribed above, by squashing, when the anodes are assembled, a sealinggasket comprising a suitable elastomer, precisely by the amountrequired, between a washer secured to the extended portions and the baseof the cell. Also, this may be accomplished by clamping the joint afterassembly-againstthe base by means of a washer which isscrewed on to "thesheath of the extended portions. Itis also possible to effect sealing bywelding on by means of their edges thin pieces of titanium or otherfilm-forming metal, replacing the washers used' hereinbefore, forprotectin the base of the cell with titanium. A third Way in which thecurrent sup lyean beprovided, comprises using a conducting" metal formaking the base of the cell and making a connection between the base andthe extended portions by means of resilient contacts arranged in anannular spacefprov'lded between the conducting core of the extendedportions, which core is bared Where it passes through the base,

and the aperture through which it passes through the.

base, sealing being effected in the same manner as hereinbefore, bymeans of sealing gaskets.

SPECIFIC DESCRIPTION OF THE INVENTION Embodiments of the presentinvention will be described by way of example hereinafter with referenceto the accompanying drawings.

FIG. 1 shows an elevational view of an anode according to the inventioncomprising two expanded or apertured sheets 1 of titanium or otherfilm-forming metal, such as tantalum, tungsten, zurconium, etc. Theseare welded along their vertical axes to the titanium sheath of acylindrical jointly-drawn member 2 comprising copper and titanium. Thetitanium sheets 1 may be in the form of a lattice. Threaded on to andwelded to the lower part of the member 2 is a washer 3 comprisingtitanium or other film-forming metal, which, by way of the toric sealinggasket 4, provides for sealing with respect to the polyester base 5 ofthe electrolytic cell. The titanium sheath of the part of the member 2which is located below the washer 3 is screw-threaded so that the anodecan be tightened to the baseof the cell by means of a nut 6. The coppercore 7 of the lower end of the member 2 is bared or exposed and carriesa sleeve 8 connected by a bunch 9 of copper wires to the electriccurrent supply rod 10. The vertical edges of the titanium sheets 1 areconnected by welding by means of members which are also made of expandedtitanium sheets.

FIG. 2 shows an elevational view of the lower part of an anode accordingto the invention having its extended portion which is gripped in thebase of the cell, the anode itself being made as described hereinbeforewith reference to FIG. 1. The extended portion 11 is a cylindricaljointly drawn member comprising copper and titanium. The copper core ofthe lower part of the copper-titanium member is exposed at 12 over aheight corresponding to the thickness of the base of the cell, the basebeing preferably made of cast aluminium and indicated by reference 13. Apassage 14 in the copper core permits the temperature of the member tobe reduced by circulating liquid nitrogen therein, so that assembly anddismantling can be effected by shrink-fitting as described hereinabove,the machining tolerances of the copper core and the bore of thecorresponding hole in the base of the cell being gauged in consequence.

Protection from corrosion is effected in the following manner: the base13 of the cell is covered by a titanium sheet 15 in which are providedcircular apertures coaxial with the electrode extended portions. Theedge of the apertures is relieved at 16; a washer-shaped member 17provided with a relieved edge 18 and made from a titanium sheet of thesame thickness as the titanium sheet 15 is welded at 19 to the sheath 20of the member 11, and the edges 16 and 18 are welded at 21. The weldingcan be ground off before dismantling the anode.

FIG. 3 also shows another mode of gripping an anode extended portion ofan anode of the invention in the base of the cell. This Figure againshows the cylindrical copper-titanium member 1 l, the sheath 20 of themember 11, the copper core exposed at 12 at the lower end of the member11, and the cooling passage 14. In this construction, the base 13 of thecell is covered with a titanium sheet 22 provided with circularapertures through which the extended portions pass. Welded to the sheath20 is a titanium washer 23 for sealing to the base by means of a toricseal 24 which is crushed or flattened during assembly.

FIG. 4 shows an elevational view of the lower part of an anode extendedportion, and the means for electrical connection between the core of theextended portion and the metal base of the cell. This Figure shows thecopper-titanium jointly drawn member 25 covered with a sheath 26, awasher 27 welded to the sheath 26, and a toric seal 28. The lower baredend 29 of the member 25 is here provided with an electrolyte leakagepurge hole 30, and terminated by a screw-thread. The copper base 31 ofthe cell has apertures through which pass the exposed ends of thejointly-drawn members, and is protected by a titanium sheet 32 havingapertures with turned-down edges, corresponding to the apertures in thebase 31. The diameter of the apertures in the base is such that anannular space is provided, for positioning rings with multiple resilientcontact means 33 for making an electrical connection between theextended portions and the base of the cell which serves in thisconstruction as a general current input. The electrode extended portionis secured by clamping by means of a nut 34 which is screwed on to thescrewthreaded end of the core.

In the foregoing embodiments, it is to be understood that where atitanium component is referred to, it may be substituted with acorresponding component fashioned of another film-forming metal or alloythereof.

The terms and expressions which have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theinvention claimed.

What is claimed is:

l. A method of providing a replaceable anode assembly in an electrolyticdiaphragm cell, said cell comprising a plurality of verticalsubstantially flat and hollow anodes formed, as regards at least one oftheir two substantially parallel faces, by a sheet of a film-formingmetal, said anodes being secured to the base of the cell by means ofextended portions which pass through the base, said extended portionscomprising a core made of a metal which is a good electrical conductor,which core is covered by a sheath made of a film-forming metal, a goodelectrical contact being ensured between the sheath and the core, saidbase of the cell being of an electroconductive metal, which base isprotected by a sheet of film-forming metal, said core of said extendedportions is exposed where it passes through the base of said cell,characterized in that sealing between said anode and said base iseffected by welding cup-shaped washers of film-forming metal affixed tosaid extended portions of said anodes and having a raised edge, to thefilm-forming metal sheet which protects the base of the cell, wherebysaid film-forming metal sheet which has a raised edge corresponding tothe raised edge of said cup-shaped washers is welded at the raised edgesof said cup-shaped washers to effect a seal.

2. A method in accordance to claim 1, whereby the core of said extendedportions of said anode where it passes through the base of said cell isgripped by the metal of said base by shrink-fitting by temperaturedifference.

1. A METHOD OF PROVIDING A REPLACEABLE ANODE ASSEMBLY IN AN ELECTROLYTICDIAPHRAGM CELL, SAID CELL COMPRISING A PLURALITY OF VERTICALSUBSTANTIALLY FLAT AND HOLLOW ANODES FORMED, AS REGARDS AT LEAST ONE OFTHEIR TWO SUBSTANTIALLY PARALLEL FACES, BY A SHEET OF A FILM-FORMINGNETAL, SAID ANODES BEING SECURED TO THE BASE OF THE CELL BY MEANS OFEXTENDED PORTIONS WHICH PASS THROUGH THE BASE, SAID EXTENDED PORTIONSCOMPRISING A CORE MADE OF A METAL WHICH IS A GOOD ELECTRICAL CONDUCTOR,WHICH CORE IS COVERED BY A SHEATH MADE OF A FILM-FORMING METAL, A GOODELECTRICAL CONTACT BEING ENSURED BETWEEN THE SHEATH AND THE CORE, SAIDBASE OF THE CELL BEING OF AN ELECTROCONDUCTIVE METAL, WHICH BASE ISPROTECTED BY A SHEET OF FILM-FORMING METAL, SAID CORE OF SAID EXTENDEDPORTIONS IS EXPOSED WHERE IT PASSES THROUGH THE BASE OF SAID CELL,CHARACTERIZED IN THAT SEALING BETWEEN SAID ANODE AND SAID BASE ISEFFECTED BY WELD-
 2. A method in accordance to claim 1, whereby the coreof said extended portions of said anode where it passes through the baseof said cell is gripped by the metal of said base by shrink-fitting bytemperature difference.